Process for producing porous oil shale products



H. E. BOWERS 2,776,210

PROCESS FOR PRODUCING POROUS OIL. SHALE PRODUCTS lIan. 1, 1957 Filed Dec. '7, 1955 INVENTOR. HAROLD E. BOWERS ATTORNEYS -no utility under present processes.

United States .Patent ce PROCESS `FOR PRODUCING-POROUS OIL SHALE .PRDUCTS Hrold'E. Bowers, Dayton, `0hio,-assignor to The Com- Wmonwealth Engineering ,Company Aof hio, Dayton,

Ohio, a corporation of Ghio ApplicationDecember 7, 1953, SerialNo. 396,589

3'Claims. (Cl. 1116-40) This invention relates to building materials and more particularly to porous building materials such as bricks,

slabs, boards, tiles and the like derived from oil bearing shales.

The production of oilfrom shale has increased in im- The ess; one important factor is that only about 20-30% of the natural shale is convertible, the remainder having An important object this-invention is `the provision of a process which utilizes the material hitherto wasted.

Aprimary object-of this invention is the provision of products from the spent shale or shale waste, which Aproducts have a high degree of saleability in present markets and will accordingly render commercially feasible the production of roil from the shale also.

The shales most suitable for the practices of the `in- `vention occur in abundance, are relatively low grade and Weight percent on fresh shale This invention contemplates that the hard, oil bearing shale will `be ground-to a suitable mesh, shaped to the form of a desired article of manufacture, pressured to @compact 'the particles and then fired; the firing may be effected under such conditions that the carbonaceous matter is distilled from the article without deformation thereof.

Where desired a binder material may be incorporated :in I,the ground `oil shale prior to the molding thereof. Such binder should be selected to be without substantial effect on the carbonaceous matter of the oil shale and -to `not interfere v.with the evolution of the carbon bearing `.compounds from the shale in the course of firing. Such `materials include sodium silicate and Portland -cement .in amounts of between about 515% by weight of the shale.

The invention will be more fully understood by reference to the following detailed description and accompanying `drawing wherein:

Figure l is a schematic view of apparatususeful in the practice of the invention;

2,776,210 `Patented Jan. f1, 'v1-9,57

Figure 2 is a perspective view of an article of manufacture in the form of aporous rigid building material structure produced kin accordance with the -process .of invention; and

Figure 43 is a view of press apparatus useful in the shaping of articles of manufacture. i

Referring to the drawing and first' particularly to Fig-- ure 3 there is shown at 1 a press, actuated hydraulically or by other suitable means having a lowerlplaten 3 and an upper platen 5. Ram 7 is actuable to bring the platens toward eachother to apply a suitable pressure as pounds per square inch to the material 9 in the cavities of mold 11 to shapethe material to a brick-like form.

The material in mold 11 is rst prepared by .grinding a shale the ash of which shale preferably conforms substantially to the range of @formulations set out hereinbefore; the shales Vary slightly in hardness and while they may usually be ground dry steaming of the shale Vprior ,to grinding facilitates the operation. Steaming where employed may beeffected onfsuitable screens which retain the broken rock-like shale pieces and permit the steam to be passed upwardly therethrough.

Grinding toa particle size in the range of 20-100 Vmicrons is readily achieved `in .the dry state with most shales; this dry powdery material may then be simply .placed in the various cavities of ymould 1l, the `press closed and the material formed to brick-like shape; heat of up to about 212 F. may be utilized although not generally required since the original waxy shale is relatively free of moisture.

The application of heat at the pressing .operation is usually beneficial however if the shale has been subjected to steaming prior to or during grinding.

As shown in Figure l a kiln 13 having metal framework 14 and a lining 15 of rebrick is provided with tracks 17; trucks 19 may be employed to carry the shale formed at the press into the kiln. The kiln is provided with doors 21, 23 and gaskets 27, 29 which may be carried on the doors; the doors 'have secured thereto .at their .upper ends cables as cable`36 which cable is operable over pulley 32 in guide 30 to raise the door 23;

vbolt means 25 are effective to compress the `gasket in the duit 33 has the exterior end thereof .connecting with a suitable supply 34 of an inert Vgas such as CO2; valve 37 is conveniently provided to control the CO2 flow to the kiln.

Conduit 35 is provided with a valve 40 and a suitable condensing tower 41 for the recovery of volatiles passing outwardly of the kiln; if desired this towermay suitably have refining apparatus associated therewith for the further processing of the volatiles or the condensing tower may be replaced by such refining apparatus.

A third conduit 43 communicates with conduit 35 and is itself provided with valve 45. The remote end of conduit 43'is connected to a vacuum pump 47 for effecting exhaustion of kiln 13. Valve 46 may be suitably ,provided to close off both the condenser and pump from the kiln.

The kiln 13 is mounted on incombustible supports 49, which are preferably of concrete, and the underside of the kiln is adapted to be heated by gas flame 51 emanating from burner 53 to temperatures of about 250 F.-2800 F. To resist these temperatures the bearings for the wheels of trucks 19 are sealed in.

In the practice of the process Lof the invention the ground material molded as indicated in Figure 3 is placed in -suitable arrangement -on trucks 19; the vcover door 23 2,776,210 Y A M Y- is opened, the track portions 26 are lowered into position to meet with track 17 at the exterior of the kiln, and the trucks roll in on the tracks. Thereafter with the doors 21, 23 each lowered and the gaskets secured valve 40 is closed, valves 37, 45 and 46 are open, and the vacuum pump 47 is operated to draw carbon dioxide from the source 34 through the kiln 13. The CO2 assists in the evacuation of all air from the chamber and the kiln itself may be heating during this evacuation though the temperature of volatilization of the hydrocarbons is preferably not approached until all air is evacuated. The pump and the ow of CO2 should continue for a suiciently long time to insure that all air has been evacuated from the apparatus; valve 37 is then shut off and the pump 47 is operated to reduce the pressure in the kiln to a very low value of CO2 y As noted during this period the kiln may be heating but should not generally be above about l000 F. There- 'after with valves 37 and 45 closed and valves 40 and 46 open the temperature is raised to about l800 F. The `volatiles of the shale will distill ol between about l500 F. and l800 F. and will be passed to condenser 41 or rening apparatus as desired.

With most shales substantially complete volatilization of the hydrocarbons will have taken place upon heating for about 4 hours at temperatures of about 1800L7 F. The time will vary somewhat with the manner in which the bricks are formed and positioned in the kiln, the various production factors in such an operation are well known and need not be considered in detail it being sucient to state that generally at least about 1/2 hour will be required to insure of volatilization under high vacuum conditions at l800 F. After evacuation valves 46 and 40 are closed and the temperature within the kiln is raised to about 2000 F. to complete firing of the shale material to porous brick. This temperature varies somewhat with the particular shale and is most alected by the alkali content thereof; the temperature must of course be maintained below the softening point of the shale residue brick.

Upon the completion of tiring and with the temperature still high valve 37 may be opened to introduce a pressure of carbon dioxide (valves 40 and 46 being closed) to permit the end doors 21, 23 of the kiln to be opened. This requires that valve 37 be open only for a short period and it is closed before the doors themselves are raised. Alternatively other means may be provided for the breaking of the vacuum within the chamber to permit the end doors to be opened. The trucks 19 from within the kiln are then moved leftwardly as shown in Figure 1 and other trucks are moved into the kiln, the doors closed and the process repeated.

Between operations the intensity of the flame 51 may be reduced, but in general it will not be found necessary to discontinue heating entirely as the entrance of air and the new charge is sufficient to materially cool the kiln. It is to be noted in this connection that the volatile hydrocarbons may be cycled to a supply to be utilized in the kiln heating if desired; in such cases the hydrocarbons are preferably treated to remove lower boiling constituents prior to combustion.

The product of the operation is illustrated in Figure 2 and is a porous material, the pores being relatively small, the brick being of a very homogeneous grainless structure due to the fact that the hydrocarbons themselves are substantially uniformly dispersed in the natural shale. Such bricks or similarly other blocks, slabs, panels or tiles of the same material may be subjected to machining operations, are absorbent, and find utility particularly as building materials.

As set out hereinbefore the ground material prior to subjection to the distillation Operation and prior to the compaction thereof may have mixed with it small amounts of other material such as -15 percent by weight of sodium silicate or Portland cement. Where a sodium silicate solution is employed the ratio of SiOz to N20 should not exceed 4:1 to avoid brittleness in the product. The sodium silicate during the firing will tend to permeate the shale mass and to be adsorbed thereby resulting in good adhesion of the particles.

The Portland cement which in slurry form is mixed with the oil shale itself normally sets hard and this characteristic is reected in the producttending to make the porous shale residue brick hard and very inexible. A clay slurry may also be employed and in fact the clay may in some cases be predominant, the oil shale being introduced to provide on tiring of the clay a porous structure.

It is generally desired to heat platen 3 or press 1 to permit excess water to be removed at the pressing stage. The pores of the product will in general be somewhat larger when an aqueous slurry of Portland cement or of the silicate is employed due to the volatilization of the water during the early stages of the distillation operation.

It is to be noted in this latter respect that where water is incorporated into the ground shale mass valve 40 is not opened until the water is completely driven off which will normally be at a temperature considerably less than 250 F., the water being evacuated through the pump 47. Such procedure requires that the kiln be permitted to cool materially between operations and always it is necessary to complete evacuating the interior of the kiln of water, oxygen, etc. before raising the temperature above l500 F.

The product, when water is incorporated into the shale mass, is subject to somewhat greater shrinkage during the processing and accordingly the pores Will tend to become somewhat closed by the shrinkage. The porosity always is greater than 10% of the volume and normally, depending upon the volatile content of the shale, the voids exceed 20% by volume of the article.

The product, Whether it has a binder incorporated therein or not, is of relatively light weight, suitable for all general building material conditions requiring rigid structures and may be ornamented or painted in much the same manner as ordinary clay bricks.

It is further to be noted that the product of invention, the chemical constitution of which corresponds to the ash of the original shale, may be attained by ring the bricks or other articles without care to the preservation of the hydrocarbons. Such procedure is economically without merit presently however.

It will be understood that this invention is susceptible to modification in order to adopt it to different usages and conditions and accordingly, it is desired to comprehend such modications within this 'invention as may fall within the scope of the appended claims.

I claim:

l. In a process of producing a porous, non-brittle, homogeneous, grainless building material structure the steps of: (a) grinding oil shale to a particle size in the range of about 20-100 microns; (b) compressing the particles of oil shale with a sodium silicate binder while heating the same to form a brick-like body; (c) evacuating and heating a closed spacing with the brick-like body therein; (d) ilushing the spacing with carbon dioxide; (e) raising the temperature within the spacing sufficiently to distill ofiC volatiles of the formed body of the shale; and (f) sintering the material after completion of the distillation.

2. In a process of producing a porous, non-brittle, homogeneous, grainless building material structure, the steps of: (a) grinding oil shale to a particle size in the range of about 20-100 microns; (b) compressing the particles of oil shale with a binder selected from the group consisting of `sodium silicate and Portland cement while heaating the same to form a brick-like body; (c) evacuating and heating a closed spacing with the bricklike body therein; (d) flushing the spacing with a nonoxidizing gas to evacuate all air from the spacing; (e)

5 raising the temperature within the spacing suciently t0 distill oi volatiles of the formed body of the shale; and (f) sintering the material after completion of the distillation.

3. In a process of producing a porous, non-brittle, homogeneous, grainless building material structure, the steps of (a) grinding oil shale to a particle size in the range of about 20-100 microns; (b) compressing the particles of oil shale with a binder selected from the group consisting of sodium silicate and Portland cement while heating the same to form a brick-like body; (c) evacuating and heating a closed spacing with the bricklike body therein; (d) iiushing the spacing with carbon dioxide; (e) raising the temperature within the spacing suciently to distill off volatiles of the formed body of the shale; and (f) sintering the material after completion of the distillation.

6 References Cited in the le of this patent UNITED STATES PATENTS 1,583,521 Boynton May 4, 1926 2,099,342 Lemmerman Nov. 16, 1937 2,543,987 Ramsay Mar. 6, 1951 2,603,570 Bole July 15, 1952 2,627,642 Osborne Feb. 10, 1953 FOREIGN PATENTS 413,238 Great Britain July 12, 1934l 385,624 Germany 1923 388,662 Germany 1924 439,464 Germany 1927 OTHER REFERENCES U. S. Dept. of Interior, Bureau of Mines, Bulletin 468 (1949), pages 385, 573 and 580. 

1. IN A PROCESS OF PRODUCING A POROUS, NON-BRITTLE HOMOGENOUS, GRAINLESS BUILDING MATERIAL STRUCTURE THE STEPS OF: (A) GRINDING OIL SHALE TO A PARTICLE SIZE IN THE RANGE OF ABOUT 20-100 MICRONS; (B) COMPRESSING THE PARTICLES OF OIL SHALE WITH SODIUM SILICATE BINDER WHILE HEATING THE SAME TO FORM A BRICK-LIKE BODY; (C) EVACUATING AND HEATING A CLOSED SPACING WITH THE BRICK-LIKE BODY THEREIN; (D) FLUSHING THE SPACING WITH CARBON DIOXIDE; (E) RAISING THE TEMPERATURE WITHIN THE SPACING SUFFICIENTLY TO DISTILL OFF VOLATILES OF THE FORMED BODY OF THE SHALE; AND (F) SINTERING THE MATERIAL AFTER COMPLETION OF THE DISTILLATION. 